Assetize.com the marketplace to sell and buy online accounts, well-known for selling Facebook vanity URL’s, has launched a new service targeted at Twitter users with unused, unwanted accounts.

This is the same concept from Facebook vanity URL’s carries over to Twitter.

Assetize will let you park Twitter accounts, like domain names, for future use and in the meantime put ads on the account while you sit back and make money. To park your Twitter account, simply register with Assetize for an invite, then put in all of your account information, give keywords related to the parked account, and Assetize will then place ads on the account that are supposedly relevant to keywords you specify. In order to apply for the private beta, your Twitter account must have at least 200 followers.

Assetize.com currently has support for parked accounts at Blogger/Blogspot, Friendfeed, Gmail, Google Groups, Google Voice, Ning, Twitter, Wordpress, and Yahoo.